I've realised, over time, that certain foods really boost me, some in a good way(eggs(if in moderation), high-meat(in a different way), oysters,cod-liver-oil, many types of raw shellfish), and one in a bad way(raw dairy). I've been trying some raw cod liver oil for 6(?) months now, partly to offset any occasions when I eat crappy, grainfed meats(increasingly rare, as I've found more grassfed opprtunities abroad etc.). Anyway, I was thinking:- raw oysters and raw fermented cod-liver-oil (and raw eggs?) contain vitamin D, not to mention some PUFAs, so that might explain it. Just a thought.